穿越长江盾构隧道施工关键技术研究

Research on Key Technologies of Shield Tunneling across Yangtze River

某穿越长江盾构隧道工程,具有“长、大、高、差”特点,即独头掘进线路长(10.226 km),盾构隧道埋深大(51.5 m),承压水头压力高(0.73 MPa),地层差(石英含量40%~60%的粉土、粉砂)。在长江南北两岸分布厂房、长江大堤、地下管线等建筑物。穿越长江采用了国内首个7.95 m小直径常压刀盘泥水平衡盾构机施工,实现了常压更换刀具。盾构机主轴承设计寿命15000 h以上,主驱动密封耐10 bar高压,安装5道盾尾刷,其中2道盾尾刷可换。采取盾构机自动化监测沼气和集中抽排沼气工艺,科学的泥浆制造系统,陀螺定向投点测量方法,针对性盾构掘进参数,盾构水中接收,留置盾尾接收等系列方法,顺利完成长江穿越。

Engineering Yangtze River shield crossing section is characterized by"long,large,high and poor",that is,the single heading line is 10.226km long,the buried depth of the shield tunnel is 51.5m,the water pressure of the confined head is 0.73Mpa,and the silt and silty sand stratum with 40-60%quartz content.Buildings such as workshops,the Yangtze River levee,and underground pipelines are distributed on both sides of the Yangtze River.The first 7.95m small-diameter atmospheric cutter head slurry balance shield machine was used for tunneling across the Yangtze River,realizing the replacement of cutters at atmospheric pressure.The design life of the main bearing of the shield machine is 15000h,and the main drive seal is resistant to 10bar high pressure.Five shield tail brushes are installed,two of which can be replaced.The Yangtze River crossing was successfully completed by adopting a series of methods,such as automatic monitoring of biogas by shield machine and centralized biogas extraction and drainage process,scientific slurry manufacturing system,gyro directional dropping point measurement method,targeted shield tunneling parameters,shield tunneling in water,and retaining shield tail receiving.